2003 ZTS - horrible gas mileage - 16.3mpg - HELP

whynotthinkwhynot · Sep 29, 2012

For anyone else concerned with fuel degradation, call your congressman and suggest that we mobilize the ethanol industry for conversion to isobutanol that reduces emissions better than ethanol and doesn't degrade fuel or fuel systems.

PWGuy · Sep 30, 2012

whynotthinkwhynot said:
It seems like you have the best advice so far. As long as the engine is running smoothly, there should be no other problems.

1) Correct your mileage calculation- use the method BCZX3 suggested.
2) The ECU reset shouldn't be done without doing the A/F reset at the same time. This requires you to idle the engine in P or N for 5 minutes after it is dropped out of high idle mode. When the test is finished, the idle will drop slightly. With her short driving- it might not have reset the A/F yet. I'd go out and start the car and let it idle for 7 mins exactly- TIMED. You can use the electronic odometer trick to see if the idle drops slightly after 6 mins or so. That will indicate it's done. I'd expect idle to be around 1100 for a car that has not passed this test, and 800 (IIRC) for an AT in N. It might be lower, but that is not bad unless the idle is extremely low in gear- like 500.
3) I didn't see mileage, or engine. We've gathered it's an AT, but we need to know the engine. Mileage is important also because if you're approaching 130k+ or so, and the timing belt has not been replaced, that would explain some of the issues.

Honestly, with a 2.9 mile drive, I'd only expect about 21-23 mpg, and yes, as Iminhell suggested, you might be experiencing fuel degradation. If nothing else, I'd give some Sta-Bil a shot- make sure you get the gas type not diesel. Finally- your fuel filter is due for a change. Yes I know, way under the 20k mark, but I do recommend that as 20-30k or 1 year. I change the wife's yearly, she puts about 10k per year on the van. It will be dirty.

1) Will put this into practice asap
2) I reset the ECU and waited 12 minutes. It idled at 1100 until a number of minutes passed, then dropped to 800 as you described. By all accounts, I've done it correct, right?
3) It is an auto with 130k miles and yes it needs TB/WP maintenance
4) I'm not expecting more than 21-23mpg, honestly. I'll give Sta-Bil a shot for gasoline engines. Also, I changed the fuel filter last year with a brand new Motorcraft unit - the car was barely driven 5,000 miles since then! (Winter car and now a short daily drive commuter). Are you serious that I need to change it yet again??? If so, maybe I should seafoam FIRST. Thoughts?

whynotthinkwhynot · Sep 30, 2012

Yep, I do change my wife's filter yearly. She does about twice that in mileage. Filter manufacturer doesn't really matter much when it comes to fuel filters. When you let the gasoline age like that it begins to separate and make all sorts of groovy stuff that sticks in the filters.

You can probably get away with waiting until after the winter if you want. I said yearly, you said November '11 of last year, so it's not quite a year. I'm not sure if your situation is worse than ours but I do know that 90% of the people out there on the road never change fuel filters. LOL We do get about halfway to the filter life in miles.

VEGAS · Sep 30, 2012

Of course its a Automatic, his wife drives it

j/k

I think its the wheel bearings getting old, they drag a bit more and with our automatics its another loss.. Automatics loose efficiency compared to the manuals when they get around 100k miles.. , yes I own both a manual and auto and I see a HUGE difference. You should be getting mid 20s even when car is not running optimal.. I would remove the tires, check for drag on spindals.

I have gotten in to the habit of popping into neutral when I slow down... lowers RPM of engine faster then leaving it in gear and car seems to stop JUST a touch faster, also less drag at a stop on motor.. I see 2 or 3 mpg difference.

sailor · Sep 30, 2012

Plenty of good advice already, especially BC's & Whynot's comments.

All I can add is that "warming it up" before driving will REDUCE the MPG, not improve it!

And that I've seen a typical 5 mpg drop in mileage from winter tires instead of high mpg summer tires alone, e.g. - a vehicle that was consistent at 30 mpg summer went to 25 mpg with winter tires with no changes in driving BEFORE the weather got colder & winter fuel was involved.

Tires & 2.9 mile drives will give these results, my Focus that gets about 28/29 in "mixed" driving has gotten as low as 18 in strictly local driving (short trips only) and that was on summer tires... Same car will get high 30's on the road (highway only).

Do all the maint. required for the best results possible of course, but it seems like you're just dealing with a "worst case scenario" of real world driving....

An OLD hint for cars subject to this type of use is to take it out for longer trips as often as possible, the proverbial Sunday Drive is actually good for it! Lets it get warm enough, long enough to clean out some of the condensation & other crud that doesn't get a chance to evaporate in daily use, and even 'burns out the carbon" a bit. Modern engines with electronic fuel injection aren't as bad in this regard as old carbureted cars in this regard, but it still helps....

Luck!

PWGuy · Oct 1, 2012

sailor said:
Plenty of good advice already, especially BC's & Whynot's comments.

All I can add is that "warming it up" before driving will REDUCE the MPG, not improve it!

And that I've seen a typical 5 mpg drop in mileage from winter tires instead of high mpg summer tires alone, e.g. - a vehicle that was consistent at 30 mpg summer went to 25 mpg with winter tires with no changes in driving BEFORE the weather got colder & winter fuel was involved.

Tires & 2.9 mile drives will give these results, my Focus that gets about 28/29 in "mixed" driving has gotten as low as 18 in strictly local driving (short trips only) and that was on summer tires... Same car will get high 30's on the road (highway only).

Do all the maint. required for the best results possible of course, but it seems like you're just dealing with a "worst case scenario" of real world driving....

An OLD hint for cars subject to this type of use is to take it out for longer trips as often as possible, the proverbial Sunday Drive is actually good for it! Lets it get warm enough, long enough to clean out some of the condensation & other crud that doesn't get a chance to evaporate in daily use, and even 'burns out the carbon" a bit. Modern engines with electronic fuel injection aren't as bad in this regard as old carbureted cars in this regard, but it still helps....

Luck!

Good to know about the winter tires - I had no idea they would negatively affect MPG by that much.

However, my tires are inflated to 40 psi..

1hotfocus · Oct 1, 2012

whynotthinkwhynot said:
It seems like you have the best advice so far. As long as the engine is running smoothly, there should be no other problems.

1) Correct your mileage calculation- use the method BCZX3 suggested.
2) The ECU reset shouldn't be done without doing the A/F reset at the same time. This requires you to idle the engine in P or N for 5 minutes after it is dropped out of high idle mode. When the test is finished, the idle will drop slightly. With her short driving- it might not have reset the A/F yet. I'd go out and start the car and let it idle for 7 mins exactly- TIMED. You can use the electronic odometer trick to see if the idle drops slightly after 6 mins or so. That will indicate it's done. I'd expect idle to be around 1100 for a car that has not passed this test, and 800 (IIRC) for an AT in N. It might be lower, but that is not bad unless the idle is extremely low in gear- like 500.
3) I didn't see mileage, or engine. We've gathered it's an AT, but we need to know the engine. Mileage is important also because if you're approaching 130k+ or so, and the timing belt has not been replaced, that would explain some of the issues.

Honestly, with a 2.9 mile drive, I'd only expect about 21-23 mpg, and yes, as Iminhell suggested, you might be experiencing fuel degradation. If nothing else, I'd give some Sta-Bil a shot- make sure you get the gas type not diesel. Finally- your fuel filter is due for a change. Yes I know, way under the 20k mark, but I do recommend that as 20-30k or 1 year. I change the wife's yearly, she puts about 10k per year on the van. It will be dirty.

Just tried the a/f reset, after a minute or so idle is at 800, after 7 minutes idles around 690-710

Sent from my SAMSUNG-SGH-I717 using Tapatalk 2

PWGuy · Oct 1, 2012

VEGAS said:
Of course its a Automatic, his wife drives it j/k

I think its the wheel bearings getting old, they drag a bit more and with our automatics its another loss.. Automatics loose efficiency compared to the manuals when they get around 100k miles.. , yes I own both a manual and auto and I see a HUGE difference. You should be getting mid 20s even when car is not running optimal.. I would remove the tires, check for drag on spindals.

I have gotten in to the habit of popping into neutral when I slow down... lowers RPM of engine faster then leaving it in gear and car seems to stop JUST a touch faster, also less drag at a stop on motor.. I see 2 or 3 mpg difference.

I will remove the tires and check for drag on the spindals. I assume I just jack up one side and spin the tire to see if any dragging, similar to brake drag or caliper sticking? And I assume I do this for all four sides, correct?

Overall, you are right, we should be getting AT A MINIMUM low 20s in MPG.

VEGAS · Oct 2, 2012

Each spindle must be checked and tires should be removed to see if it feels overly stiff. It wont spin free, but will have a SLIGHT drag, However sometimes this to wont tell the whole story, sometimes just replacing them with OEM is the only way to know.

IH84DZ · Oct 2, 2012

I see a lot of variables in here that don't make your mileage figures a shocker. Unless you are calculating fuel economy by filling your tank, logging mileage and filling the tank at the same pump again while dividing the miles driven by gallons used - your fuel usage figures are terribly inaccurate. This may sound unacceptable given you are using the fuel gauge but if you understood how a fuel gauge worked it would make more sense. They are accurate estimations of fuel level, not accurate measurents of fuel level.

A drive of less than 3 miles (especially in cool temps) is likely not enough time for the engine to reach closed loop. In open loop it fuels the engine based on a programmed table that is certainly rich of stoich and thus it will consume more fuel in open loop than it will in closed loop. This is aside from all the other problems you can expect with such a short run cycle.

Your tire compound will negatively affect fuel economy as well because they have more drag compared to a street tire - regardless of how much air you put in them

It is a good idea to check for dragging brakes - especially if you've had brake issues in the past

How much extra weight is in the car?

What is the ethanol content of the fuel being used?

Your woman may have poor driving habits. I can make a motorcycle get 10mpg if I try hard enough........

Get rid of the K&N filter. MAF based Fords are notorious for aftermarket filters (especially "performance" filters that use oil to trap FOD) messing with the air turbulence across the MAF sensor and/or contaminating the sensor with oil. Comparing what mileage you get with a go-fast air filter to what others get with paper filters isn't a very valid comparison.

PWGuy · Oct 2, 2012

IH84DZ said:
I see a lot of variables in here that don't make your mileage figures a shocker. Unless you are calculating fuel economy by filling your tank, logging mileage and filling the tank at the same pump again while dividing the miles driven by gallons used - your fuel usage figures are terribly inaccurate. This may sound unacceptable given you are using the fuel gauge but if you understood how a fuel gauge worked it would make more sense. They are accurate estimations of fuel level, not accurate measurents of fuel level.

A drive of less than 3 miles (especially in cool temps) is likely not enough time for the engine to reach closed loop. In open loop it fuels the engine based on a programmed table that is certainly rich of stoich and thus it will consume more fuel in open loop than it will in closed loop. This is aside from all the other problems you can expect with such a short run cycle.

Your tire compound will negatively affect fuel economy as well because they have more drag compared to a street tire - regardless of how much air you put in them

It is a good idea to check for dragging brakes - especially if you've had brake issues in the past

How much extra weight is in the car?

What is the ethanol content of the fuel being used?

Your woman may have poor driving habits. I can make a motorcycle get 10mpg if I try hard enough........

Get rid of the K&N filter. MAF based Fords are notorious for aftermarket filters (especially "performance" filters that use oil to trap FOD) messing with the air turbulence across the MAF sensor and/or contaminating the sensor with oil. Comparing what mileage you get with a go-fast air filter to what others get with paper filters isn't a very valid comparison.

0 extra weight in the car - back seats and trunk are EMPTY.

Regarding the short trip to work - should I let the car warm up? And for the record, I drive my Mazda Miata about the same mileage to the health club every other day and that is IT (I work from home). And I STILL GET 24-25 MPG! What the hell gives here with the Focus!? And the Miata is older - 1997!

You've summarized things well and I will take your advice tonight and get a new air filter, and sell the stupid K&N. I've been wondering if I simply drank the kool-aid on that one without thinking it through/researching.

The gasoline I purchase is local Mobil or BP - so whatever their standard is for ethanol content?

sailor · Oct 2, 2012

Ok, had to recheck ALL the postings on this thread just to see what I may have missed...

When doing so I noticed a comment on idle speed problems with the air conditioner on and the note that IAC might need cleaning. how's that been working overall?

FYI, so you don't feel insulted, we see a LOT of non-problems with this type of issue due to manner of figuring mileage or type of use - so we have to start with the "stupid questions" first just to make sure we aren't chasing our tails here while trying to help...

Actual history of mpg over time can be diagnostic of developing problems, in this case it really doesn't seem to be available...

With the age of the car, and the service items you've needed to replace already, I'm wondering what the total mileage is on the car and whether the timing belt has been replaced yet?

It MIGHT be time to "start with the basics", and check the mechanical condition of the engine with a compression check, then check the cam timing/replace the belt if that hasn't been done yet.

The real underlying question here is whether the mpg has been going down over time, or whether this is a sudden change in the "norm" for this car.

The 23 to 25 highway # from before you got it is already a bit low, so there may have been some issues at that time that you still haven't found & addressed.

From what you mentioned in your last post, possibly the easiest first diagnostic would be to drive the car yourself for a bit as you have the Miata, keeping track of actual miles & gallons at each fill to get a good set of mpg numbers for reference.

keep in touch here, and the members will keep throwing out Ideas as you go through the research process to find any issues with the car.

The best function of the forum is to throw out possibilities you can check when you're already out of ideas yourself. It's the thing I miss most working by myself instead of in a shop with other mechanics. The only substitute available is to talk with other friends that work on their vehicles, or for the Focus ask questions here...

luck!

PWGuy · Oct 3, 2012

Does warming up the car 7-10 minutes before my wife leaves for work get us any benefit with MPG?

PWGuy · Oct 3, 2012

sailor said:
Ok, had to recheck ALL the postings on this thread just to see what I may have missed...

When doing so I noticed a comment on idle speed problems with the air conditioner on and the note that IAC might need cleaning. how's that been working overall?

I haven't done the IAC yet since we are moving and busy - it will probably (hopefully) be cleaned in November.

sailor said:
FYI, so you don't feel insulted, we see a LOT of non-problems with this type of issue due to manner of figuring mileage or type of use - so we have to start with the "stupid questions" first just to make sure we aren't chasing our tails here while trying to help...

I understand completely. And my MPG calculation was bunk, apologies. I'm working on getting an accurate reading this week and next week to report back.

sailor said:
Actual history of mpg over time can be diagnostic of developing problems, in this case it really doesn't seem to be available...

With the age of the car, and the service items you've needed to replace already, I'm wondering what the total mileage is on the car and whether the timing belt has been replaced yet?

The car just rolled over 130,000 miles - I took possession of it November 2011 with 122,016 miles from my father-in-law. He took possession of it a few years back from the original owner when the vehicle had 92,000 miles.

sailor said:
It MIGHT be time to "start with the basics", and check the mechanical condition of the engine with a compression check, then check the cam timing/replace the belt if that hasn't been done yet.

How do I perform a compression check? Do I rent a tool from local O'Reillys and use it? I've never used one before, so I don't have a clue...YouTube, maybe?

Regarding timing belt replacement, will be next Spring before I can get to that - just too busy right now with our move and holidays coming.

sailor said:
The real underlying question here is whether the mpg has been going down over time, or whether this is a sudden change in the "norm" for this car.

The 23 to 25 highway # from before you got it is already a bit low, so there may have been some issues at that time that you still haven't found & addressed.

Apologies but it was about 23 city before this change occurred to less than 20 city. This car rarely gets on the highway. And after I installed the new Motorcraft Fuel Filter in November 2011, I put in some Lucas Fuel Injector cleaner - FYI.

sailor said:
From what you mentioned in your last post, possibly the easiest first diagnostic would be to drive the car yourself for a bit as you have the Miata, keeping track of actual miles & gallons at each fill to get a good set of mpg numbers for reference.

keep in touch here, and the members will keep throwing out Ideas as you go through the research process to find any issues with the car.

The best function of the forum is to throw out possibilities you can check when you're already out of ideas yourself. It's the thing I miss most working by myself instead of in a shop with other mechanics. The only substitute available is to talk with other friends that work on their vehicles, or for the Focus ask questions here...

luck!

Yep, will do that

sailor · Oct 3, 2012

Warm up vs. mpg

PWGuy said:
Does warming up the car 7-10 minutes before my wife leaves for work get us any benefit with MPG?

Nope, best "warm up" for mpg & vehicle longevity is still to fire it up, then drive away "normally" - while trying to avoid any "extremes" in acceleration, braking etc. until the car has a chance to warm up.

The current crop of vehicles generally drives quite well, even when "cold" - yet ALL the systems are happier once they get some exercise & warm up to normal operating temperatures. Over the years I've seen some extremes of damage done when the operator didn't understand the importance of this. It's QUITE uncommon & any damage is usually cumulative over time instead of catastrophic. There are exceptions of course, and for automobiles winter weather is the worst. In Northern climes almost anything can break from the cold, & treating machines more gently when cold is a partial defense.

[wave]

PWGuy · Oct 3, 2012

sailor said:
Nope, best "warm up" for mpg & vehicle longevity is still to fire it up, then drive away "normally" - while trying to avoid any "extremes" in acceleration, braking etc. until the car has a chance to warm up.

The current crop of vehicles generally drives quite well, even when "cold" - yet ALL the systems are happier once they get some exercise & warm up to normal operating temperatures. Over the years I've seen some extremes of damage done when the operator didn't understand the importance of this. It's QUITE uncommon & any damage is usually cumulative over time instead of catastrophic. There are exceptions of course, and for automobiles winter weather is the worst. In Northern climes almost anything can break from the cold, & treating machines more gently when cold is a partial defense.

[wave]

Wow, I'm surprised by this to say the least. Ok so let me ask a different way - is it better for the engine internals, etc to warm-up the engine while parked in my driveway 10 minutes before a super short trip, like my wife driving to work? (Putting MPG aside)..

IH84DZ · Oct 3, 2012

PWGuy said:
Wow, I'm surprised by this to say the least. Ok so let me ask a different way - is it better for the engine internals, etc to warm-up the engine while parked in my driveway 10 minutes before a super short trip, like my wife driving to work? (Putting MPG aside)..

Yes. With your short trips which are not long enough for everything to reach nominal operating temperature, a best practice would be to let it idle at least 10 minutes before driving especially in temps below 50*F. Granted, you are burning fuel that isn't moving the odometer so fuel economy will go down...but....you aren't really going to be impressed with your mileage if the car never gets warm enough for closed loop either.

Thermostat, hoses, moisture in the oil, the catalytic converter, oxygen sensors, fuel vaporization, transmission - all are systems that REQUIRE a certain temperature in order to operate properly. Systems designed to be heat cycled should be expected to fail early if not properly heat cycled. My professional opinion is that the extra $ spent on wasted gas as it idles (marginal amounts, really) will more than offset the cost and hassle that may result from inadequate heat cycling.

PWGuy · Oct 3, 2012

IH84DZ said:
Yes. With your short trips which are not long enough for everything to reach nominal operating temperature, a best practice would be to let it idle at least 10 minutes before driving especially in temps below 50*F. Granted, you are burning fuel that isn't moving the odometer so fuel economy will go down...but....you aren't really going to be impressed with your mileage if the car never gets warm enough for closed loop either.

Thermostat, hoses, moisture in the oil, the catalytic converter, oxygen sensors, fuel vaporization, transmission - all are systems that REQUIRE a certain temperature in order to operate properly. Systems designed to be heat cycled should be expected to fail early if not properly heat cycled. My professional opinion is that the extra $ spent on wasted gas as it idles (marginal amounts, really) will more than offset the cost and hassle that may result from inadequate heat cycling.

Noted - thank you so much for the info

sailor · Oct 3, 2012

Rental compression gauge will work, key is to do the test in a manner that'll give useable results.

Got a battery charger?

The best way to get good numbers that I know, is to:

1. remove all spark plugs

2. reinsert plugs into their wire & ground to engine (laying them on a metal engine part that's NOT insulated from the block works) this gives the spark somewhere safe to go when you crank the engine

3. Screw adapter/gauge into the first plug hole (which end you start with doesn't matter, but #1 is by the belt end)

4. crank over engine with gas pedal to the floor until the gauge needle stops going up, then record that number - release the pressure to remove the gauge - and go to the second cyl.

5. after doing the same procedure on the second cyl., charge up the battery before doing the third & fourth (how essential this is depends on your battery condition, a good battery could do all 4, while a poor one might need charging between each to get consistent cranking speed)

6. Now you can check the results

Exact numbers can vary between gauges, the first check is to look for variation between the cylinders - this should be within 10% for an engine in good condition. For example, if you see 140 psi on 3, and one is at 125 psi - that one is JUST out of the "normal" range and bears watching in the future. If you saw one at 75 psi, the engine may have a problem and is likely running rough - time to recheck by redoing the test to confirm your results.

As a rule of thumb, 5 to 10 psi variation falls within the normal range for a good engine, while more than that should be rechecked & watched for changes (it's good practice to check compression at each engine maintenance time to get base line numbers & note any changes).

Unusually high or low numbers across the board CAN be indicative of certain issues (engine wear or carbon build up at two extremes) but it's not time to panic when you aren't sure of the particular gauge's accuracy. There are other signs & tests we can describe, besides trying a different gauge, to determine exactly what's going on if the initial results don't look good!

Luck!

sailor · Oct 3, 2012

Warm up in general

PWGuy said:
Wow, I'm surprised by this to say the least. Ok so let me ask a different way - is it better for the engine internals, etc to warm-up the engine while parked in my driveway 10 minutes before a super short trip, like my wife driving to work? (Putting MPG aside)..

Believe it or not (grin), it's actually better for the engine to warm up under light loads than to idle until warm.

Best way I can describe this, is that without any "load" on the engine, the moving parts tend to "flop around" more - creating stresses that aren't there in normal use.

Long times spent "idling" actually wear an engine MORE than normal highway driving for example, one of the many reasons "idle reduction technology" is a major issue regarding "Big Rigs" these days (Saving fuel & reducing emissions are the items in the news, but it does reduce maintenance & result in better longevity as well)

2003 ZTS - horrible gas mileage - 16.3mpg - HELP

whynotthinkwhynot

PWGuy

whynotthinkwhynot

VEGAS

sailor

PWGuy

1hotfocus

PWGuy

VEGAS

IH84DZ

PWGuy

sailor

PWGuy

PWGuy

sailor

PWGuy

IH84DZ

PWGuy

sailor

sailor

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